Cellular Communication Systems Research Articles

Interaction between Electromagnetic (EM) wave and human head: Normal adult and elderly heads

In recent years, there has been an increasing public concern about the health implications of electromagnetic (EM) wave exposure with the use of mobile telephones. In this paper, we have evaluated the EM absorption in the human head at GSM 900 MHz (Global System for Mobile telecommunications) and DCS 1800 MHz (Digital Cellular System) radiation. Two models for human head were considered. The first model was normal adult head whereas the second model was normal elderly head. First, a stratified structure of the human head is modeled. Next, a two-dimensional (2-D) cylindrical head model based on finite-difference time-domain (FDTD) method is investigated. Our previous described 2-D FDTD code based on LabVIEW has been utilized. Much attention has been paid to the induced specific absorption rate (SAR) in elderly human head.

Efficient Monte Carlo Algorithms based on Stochastic Geometry for Simulating Downlink and Uplink Cellular Communications

Stochastic geometry (SG) is increasingly utilized in modeling cellular communications systems, as it yields accurate and realistic analytical results. The most common aim of such modeling is to characterize the coverage probability in both the downlink (DL) and uplink (UL) directions. To validate these results, however, researchers need to use simulation, for which efficient algorithms are by and large not available, and that is where the present article comes in. We introduce here two SG based Monte Carlo algorithms to simulate DL and UL cellular communications efficiently and accurately. The algorithms are so comprehensive that they take the parameters of the system as input and deliver its coverage probability as output, considering in the process such details as equipment deployment, signal power, interference, and channel conditions. To demonstrate their superior efficiency, the algorithms have been analyzed rigorously. To test their accuracy, they have been coded and applied to some sample systems, producing results that match those produced analytically to within 4% in DL and 5% in UL. Although they are designed for the field of communications, the algorithms can be easily adapted for other fields where SG is also applicable, such as biology, astronomy and forestry.

Cellular network measurements can unravel spatiotemporal properties of bird movement to enhance basic and applied knowledge globally

Abstract A major problem in studying bird movement in many countries is data scarcity, precluding information about the spatial and temporal properties of avian distribution and dynamics as well as their consequences for human lives. We address this problem by proposing an innovative approach based on the relation between counts of signal attenuation of wireless communication to the presence of birds across or near wireless links of cellular backhaul networks. Wireless point-to-point communication links, on either ground level or earth-satellite links, cover the globe. We statistically relate between signal attenuation in terrestrial Commercial Microwave Links (CMLs) and bird migration. Because modern communication systems measure and often log signal levels routinely, we propose using existing signal level measurements of cellular and other wireless communication systems around the world as sensors for monitoring of bird movement. Using actual measurements from operational CMLs, we show that the daily cycle of signal attenuation during bird migration periods matched that of waterbird migration traffic rate recorded by nearby bird radar. This demonstrates the potential of the proposed method for opportunistic bird movement monitoring by CMLs across the globe, with no additional hardware installation, maintenance or communication costs.

Exosomal MicroRNAs modulate the cognitive function in fasudil treated APPswe/PSEN1dE9 transgenic (APP/PS1) mice model of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by cognitive decline stemming from the accumulation of beta-amyloid (Aβ) plaques and the propagation of tau pathology through synapses. Exosomes, crucial mediators in neuronal development, maintenance, and intercellular communication, have gained attention in AD research. Yet, the molecular mechanisms involving exosomal miRNAs in AD remain elusive. In this study, we treated APPswe/PSEN1dE9 transgenic (APP/PS1) mice, a model for AD, with either vehicle (ADNS) or fasudil (ADF), while C57BL/6 (control) mice received vehicle (WT). Cognitive function was evaluated using the Y-maze test, and AD pathology was confirmed through immunostaining and western blot analysis of Aβ plaques and phosphorylated tau. Exosomal RNAs were extracted, sequenced, and analyzed from each mouse group. Our findings revealed that fasudil treatment improved cognitive function in AD mice, as evidenced by increased spontaneous alternation in the Y-maze test and reduced Aβ plaque load and phosphorylated tau protein expression in the hippocampus. Analysis of exosomal miRNAs identified three miRNAs (mmu-let-7i-5p, mmu-miR-19a-3p, mmu-miR-451a) common to both ADNS vs ADF and WT vs ADNS groups. Utilizing miRTarBase software, we predicted and analyzed target genes associated with these miRNAs. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of miRNA target genes indicated that mmu-miR-19a-3p and mmu-miR-451a are implicated in signal transduction, immune response, cellular communication, and nervous system pathways. Specifically, mmu-miR-19a-3p targeted genes involved in the sphingolipid signaling pathway, such as Pten and Tnf, while mmu-miR-451a targeted Nsmaf, Gnai3, and Akt3. Moreover, mmu-miR-451a targeted Myc in signaling pathways regulating the pluripotency of stem cells. In conclusion, fasudil treatment enhanced cognitive function by modulating exosomal MicroRNAs, particularly mmu-miR-451a and mmu-miR-19a-3p. These miRNAs hold promise as potential biomarkers and therapeutic targets for novel AD treatments.

Parameter Estimation of Cellular Communication Systems Models in Computational MATLAB Environment: A Systematic Solver-based Numerical Optimization Approaches

Model-based parameter estimation, identification, and optimisation play a dominant role in many aspects of physical and operational processes in applied sciences, engineering, and other related disciplines. The intricate task involves engaging and fitting the most appropriate parametric model with nonlinear or linear features to experimental field datasets priori to selecting the best optimisation algorithm with the best configuration. Thus, the task is usually geared towards solving a clear optimsation problem. In this paper, a systematic-stepwise approach has been employed to review and benchmark six numerical-based optimization algorithms in MATLAB computational Environment. The algorithms include the Gradient Descent (GRA), Levenberg-Marguardt (LEM), Quasi-Newton (QAN), Gauss-Newton (GUN), Nelda-Meald (NEM), and Trust-Region-Dogleg (TRD). This has been accomplished by engaging them to solve an intricate radio frequency propagation modelling and parametric estimation in connection with practical spatial signal data. The spatial signal data were obtained via real-time field drive test conducted around six eNodeBs transmitters, with case studies taken from different terrains where 4G LTE transmitters are operational. Accordingly, three criteria in connection with rate of convergence Results show that the approximate hessian-based QAN algorithm, followed by the LEM algorithm yielded the best results in optimizing and estimating the RF propagation models parameters. The resultant approach and output of this paper will be of countless assets in assisting the end-users to select the most preferable optimization algorithm to handle their respective intricate problems.

Модели расчета распределения уровня мощности электромагнитного поля в системах подвижной радиосвязи для малых дистанций в летний период

The statement is substantiated that for the design of mobile radio communication systems at short distances up to 1 000 m, the main recommended calculation models have a significant error, since they were created for calcula-tions of long distances (as a rule, from 1 to 50 km) and have limitations in application. Due to the fact that at the present stage of development of mobile radio communication systems, the frequency ranges are in intensive research and use not only 900 and 1 800 MHz, but also 450-800 MHz sections, as well as from 2 100 to 6 000 MHz, which were not previously used for cellular communication systems, it is necessary to propose additional models necessary for the preliminary design of 3-5 generation systems in the range from 2 100 MHz. The range of radio waves in the ranges from 2 100 to 6 000 MHz is significantly reduced compared to the ranges of 1 800 or 900 MHz. The use of classical calculation models such as the Okumura and COST-231–Hata models at distances less than 1 km is characterized by significant errors and is not recommended by the authors of the models themselves for use at short distances. To solve this problem, new models have been developed for calculating the attenuation of radio signals designed to estimate attenuation at short distances.

Random Access Preamble Design and Timing Advance Estimation for OTFS Systems in High-Mobility Scenarios

The uplink timing synchronization is indispensable for establishing a reliable link between the base station and the user equipment (UE). To tackle this problem, a new random access preamble (RAP) waveform is designed for cellular communication systems operating in high-mobility scenarios for orthogonal time frequency space systems. Meanwhile, we also propose a scheme to detect access UEs and estimate the corresponding round-trip propagation delay (i.e., timing advance (TA)). Concretely, the RAP root sequence consists of chirp sequences in the delay-Doppler domain, and the set of available RAPs is generated by cyclic shifting the root sequence. Then, the cross-correlation in the fractional Fourier domain is carried out to achieve the RAP detection and TA estimation of the access UEs. Exhaustive numerical simulation results corroborate that the proposed scheme has a superior RAP detection and TA estimation performance and exhibits sufficient robustness regarding Doppler shifts and the number of UEs.

A deep learning approach for reduce CSI feedback overhead in massive MIMO

The Massive MIMO system in FDD communication mode is still one of the indispensable technologies in future cellular communication systems. In order to reduce CSI feedback overhead and enhance the quality of CSI channel reconstruction, this paper proposes a RiCsiNet network model and designs an iNetBlock module with larger convolutional kernels and a wider network structure. By connecting parallel convolution kernels of 1 × 1, 3 × 3, 5 × 5, and 7 × 7, both the width of the network and the receptive field are increased simultaneously, enabling calculation of different feature details at each layer. The compressed CSI is accurately estimated through residual connections at the BS end. The network model proposed in this paper, when considering both the model parameter size and the estimated CSI accuracy, outperforms the existing algorithm model in the NMSE index of 70%. In this paper, we verify that using different learning rate decay algorithms to train the model, a good learning rate decay algorithm can effectively improve the quality of the model, the best result is 12% higher than the worst result. Furthermore, we demonstrate that training different network models with varying amounts of data can not only save time but also maximize CSI channel estimation quality on the BS side. Finally, the RiCsiNet model was verified using different SNR under COST2100 channel model. QuaDRiGa data sets with different truncated subcarriers are used to verify the RiCsiNet model. The CSI estimated by the RiCsiNet model all showed high accuracy.

A 28 GHz Highly Linear Up-Conversion Mixer for 5G Cellular Communications

In this paper, we present a highly linear direct in-phase/quadrature (I/Q) up-conversion mixer for 5G millimeter-wave applications. To enhance the linearity of the mixer, we propose a complementary derivative superposition technique with pre-distortion. The proposed up-conversion mixer consists of a quadrature generator, LO buffer amplifiers, and an I/Q up-conversion mixer core and achieves an output third-order intercept point of 15.7 dBm and an output 1 dB compression point of 2 dBm at 27.6 GHz, while it consumes 15 mW at a supply voltage of 1 V. The conversion gain is 11.4 dB and the LO leakage and image rejection ratio are −56 dBc and 61 dB, respectively, in the measurement. The proposed I/Q up-conversion mixer is suitable for 5G cellular communication systems.

Interference aware two-tier fair user-cell association

The deployment of heterogeneous networks (HetNets) incorporating small cells within macrocells has emerged as a predominant strategy to improve the performance of cellular communication systems. This study delves into the intricacies of user-cell association within HetNets and introduces an optimized approach that not only maximizes the sum of downlink signal-to-noise ratio (SNR) but also limits uplink interference within a dual-tier network. The suggested solution is scalable and adaptable to ultra-dense HetNets (UD-HetNets). It also facilitates various communication systems, encompassing ultra-reliable low-latency communications by leveraging a weighted cost function. Assorted simulations illustrate that optimization tools achieve the optimal solution of the proposed association problem. Comparative studies with traditional association methods signify the performance of the proposed algorithm, manifested in increased SNR values and an increased number of active users. It is shown that a trade-off surfaces between increased SNR values and increased fairness. In summary, the research emphasizes a comprehensive methodology for user-cell association, effectively addressing performance enhancement and fairness in diverse communication scenarios.

Converging Towards Open Radio Access Networks – A Comprehensive Review

Radio Access Networks (RAN) have been an integral part of the cellular mobile communication systems since the deployment of Global System for Mobile Communication (GSM) networks and later for the legacy Universal Mobile Telecommunication Systems (UMTS) and Long Term Evolution (LTE) networks. However, due to increasing demands of the users, throughput, ultra-lower latency, virtualization of the network and to cater the seamless connectivity of millions of wireless devices with the cellular networks, the advent of RAN needs to be brought under consideration. In this paper the traditional RANs are discussed with the necessity for their transition into the Open RAN (ORAN), considering all its essential parameters. The constraints of the legacy RAN architectures are explored with an overview of the RAN intelligent controllers, ORAN and its types. This paper additionally examines the function of artificial intelligence in Common Public Radio Interface (CPRI), enhanched CPRI, and xApps in terms of use cases along with the challenges associated with their deployment. The paper also present challenges and future of ORAN.

Исследование биологического действия электромагнитных полей стандартов сотовой связи 2-5G на некоторые показатели оксидативного стресса у животных: эффекты воздействия и последействия

The fifth generation (5G) cellular networks development with operation various previous cellular standards indicates a change of electromagnetic background by new sources, and has a human health risk factor. The purpose of the research was to evaluate the electromagnetic field biological effects of monthly multi-frequency electromagnetic field exposure from 2-5G cellular communication systems on some indicators of oxidative stress in the blood of rats and the aftereffect state. The first group of animals exposed by electromagnetic field from 2-4G base stations (central frequencies 1.8; 2.1 and 2.6 GHz), second – 5G with central frequencies 3.5; 28 and 37 GHz. The pro-oxidant and antioxidant components concentrations (diene conjugates, ketodienes) and catalase in blood rats were investigate. Results showed the possibility of pro-oxidant and antioxidant components concentrations imbalance which is a consequence of the oxidation processes activation and an increase body’s adaptive mechanisms, in particular, antioxidant protection. The electromagnetic field biological effect of 5G NR/IMT-2020 exposed is unstable, as opposed to the consequences of 2-4G electromagnetic field exposure.

Evaluation and Improvement of QoE and QoS Parameters in Commercial 5G Networks: 5G-TOURS Approach

Cellular communication systems have become an urgent part not only of our everyday life, but also play a big role in the process of building a fundamentally new intelligent concept of the digital world. We are currently in the development phase of 5G cellular networks on the way to their transformation to 6G. 5G has become a truly revolutionary technology, able to use all available advantages, technologies and create the digital world of the future. Therefore, 5GPPP within the framework of the Horizon 2020 program was granted funding for a large number of research projects, the purpose of which was to test the proposed innovative solutions, to combine efforts with cellular operators, vendors, etc., in order to test the real capabilities of 5G and demonstrate all the advantages to vertical industries. One of these flagship projects was 5G-TOURS. The 5G-TOURS project was aimed at improving mobility systems in the city, the e-Health industry and the tourism sector. Thus, within the framework of 5G-TOURS project was developed the special methodology for assessment of QoE and QoS and mapping between these parameters. To apply developed evaluation methodology for all the use cases of the project is very difficult, as it needs a lot of additional efforts by the partners, additional testing tools, testing procedures, etc. That is why it was decided to apply the developed approach only to one use cases in which it was possible to collect all the required data. Thus, UC 4 “High quality video service distribution” was under study to ensure the applicability of the developed approach. All the experiments were conducted in Turin, wherein a movable car, specially equipped, collected QoE and QoS data for further analysis. Thus, the methodological approach was confirmed by the results of the conducted experiments. And in the future, similar models can be developed to study the correlations of service quality parameters and user experience for any developed use cases.

A Study on Microstrip Array Antenna with FSS for Next Generation Cellular Communication

Abstract: Fifth-generation wireless, often known as 5G, is the next version of cellular technology and is intended to provide major improvements to the speed and responsiveness of wireless networks. In addition, the increased bandwidth and improved antenna technologies that come with 5G make it possible for a significant increase in the quantity of data that can be transmitted via a wireless network. In order to build a successful next-generation cellular communication system in the terahertz (THz) regime, it is necessary to create high-directivity antennas, which will enable the signal to travel further than 0.1 km. This will allow the system to function effectively. Concurrently, large bandwidth antennas should be designed in order to facilitate the information's transmission

A UAV-based coverage gap detection and resolution in cellular networks: A machine-learning approach

The use of unmanned aerial vehicles (UAVs) to extend the coverage of terrestrial base stations (BSs) in cellular communication systems has been gaining increasing interest in recent years. This is due to the ease of deploying UAV-mounted BSs within relatively short times with low associated costs. In this work, we formulate the problem of deploying UAV-mounted BSs to mitigate the coverage gaps of the terrestrial BSs of cellular networks in some geographic regions. We then devise a technique that provides the optimal bound of the solution to the coverage gap detection and mitigation problem. We also propose a machine-learning (ML) based technique to provide a real-time solution for deploying UAVs to determine and mitigate the coverage gaps. In both solutions, namely, the optimal and ML-based solutions, the deployment of the UAVs is done in such a way that addresses the coverage gaps at the minimum possible cost. Simulation results show that our ML-based technique performs quite closely to the performance of the optimal solution, at a significantly lower complexity, and hence fulfills the real-time requirements of such deployments. It also provides significantly better performance results than a common benchmark solution from the literature.

Optimal Radio Propagation Modeling and Parametric Tuning Using Optimization Algorithms

Benchmarking different optimization algorithms is tasky, particularly for network-based cellular communication systems. The design and management process of these systems involves many stochastic variables and complex design parameters that demand an unbiased estimation and analysis. Though several optimization algorithms exist for different parametric modeling and tuning, an in-depth evaluation of their functional performance has not been adequately addressed, especially for cellular communication systems. Firstly, in this paper, nine key numerical and global optimization algorithms, comprising Gauss–Newton (GN), gradient descent (GD), Genetic Algorithm (GA), Levenberg–Marguardt (LM), Quasi-Newton (QN), Trust-Region–Dog-Leg (TR), pattern search (PAS), Simulated Annealing (SA), and particle swam (PS), have been benchmarked against measured data. The experimental data were taken from different radio signal propagation terrains around four eNodeB cells. In order to assist the radio frequency (RF) engineer in selecting the most suitable optimization method for the parametric model tuning, three-fold benchmarking criteria comprising the Accuracy Profile Benchmark (APB), Function Evaluation Benchmark (FEB), and Execution Speed Benchmark (ESB) were employed. The APB and FEB were quantitatively compared against the measured data for fair benchmarking. By leveraging the APB performance criteria, the QN achieved the best results with the preferred values of 98.34, 97.31, 97.44, and 96.65% in locations 1–4. The GD attained the worst performance with the lowest APE values of 98.25, 95.45, 96.10, and 95.70 in the tested locations. In terms of objective function values and their evaluation count, the QN algorithm shows the fewest function counts of 44, 44, 56, and 44, and the lowest objective values of 80.85, 37.77, 54.69, and 41.24, thus attaining the best optimization algorithm results across the study locations. The worst performance was attained by the GD with objective values of 86.45, 39.58, 76.66, and 54.27, respectively. Though the objective values achieved with global optimization methods, PAS, GA, PS, and SA, are relatively small compared to the QN, their function evaluation counts are high. The PAS, GA, PS, and SA recorded 1367, 2550, 3450, and 2818 function evaluation counts, which are relatively high. Overall, the QN algorithm achieves the best optimization, and it can serve as a reference for RF engineers in selecting suitable optimization methods for propagation modeling and parametric tuning.

Energy Efficiency Analysis of the Discontinuous Reception Scheme in 5G NR Communication Systems

The purpose of this work is to analyze the energy saving schemes of user equipment in the first releases (Release 15) of the fifth generation (5G NR) cellular mobile communication systems, as well as to identify possible ways to improve the energy efficiency of these systems. The paper describes the identified drawbacks of the existing discontinuous reception scheme (DRX-scheme) used for user equipment energy saving in 5G NR. The effectiveness of discontinuous reception scheme in reducing user equipment energy consumption was analyzed in detail by simulation study for various traffic models and a key scenario for the deployment of 5G wireless cellular mobile communication systems. Analysis of the simulation results shows that the discontinuous reception scheme does not reach the upper limit of possible energy saving for all the traffic models studied for a number of reasons described in this paper.

Comment on Redmayne, M.; Maisch, D.R. ICNIRP Guidelines' Exposure Assessment Method for 5G Millimetre Wave Radiation May Trigger Adverse Effects. Int. J. Environ. Res. Public Health 2023, 20, 5267.

This article discusses the contention in the commented-upon paper that Brillouin precursors generated by 5G New Radio (5G NR) and other cellular systems are a possible cause of tissue damage at deeper layers of tissue than the power penetration depth of the carrier frequency. The original theory for Brillouin precursors from pulsed radiofrequency signals (RF-EMF) and speculation about their possible health effects dates back to the 1990's and was based on studies of the propagation of very short (nanosecond) ultrawide-bandwidth RF pulses through water. This assumption is not correct for cellular telephone signals due to their narrow bandwidth. The commented-on paper provides no alternative rationale as to why Brillouin effects should cause tissue damage from RF-EMF radiation from cellular and other communications systems. Other inaccuracies in this paper concerning thermal responses of tissue to RF-EMF are also noted.

Spectral Efficiency Analysis for Uplink Multicell Massive MIMO Cellular Communication System under Fading Channels

Spectral Efficiency Analysis for Uplink Multicell Massive MIMO Cellular Communication System under Fading Channels

Design of 28/38-GHz Dual-Band Millimeter Wave Antenna based on SIW for Future Cellular Communication Systems

Design of 28/38-GHz Dual-Band Millimeter Wave Antenna based on SIW for Future Cellular Communication Systems